//
//  NSString+MULAdditions.m
//  UniLoginSDK
//
//  Created by Song Xiaofeng on 13-12-13.
//  Copyright (c) 2013年 Mafengwo Inc. All rights reserved.
//

#import "NSString+MULAdditions.h"
#import <CommonCrypto/CommonDigest.h>

@implementation NSString (MULAdditions)
- (NSString*)mul_urlEncode
{
    return [self _stringByEscapingForURLArgument];
}

- (NSString*)mul_urlDecode;
{
    return [self _stringByUnescapingFromURLArgument];
}

- (NSString*)_stringByEscapingForURLArgument;
{
    // Encode all the reserved characters, per RFC 3986
    // (<http://www.ietf.org/rfc/rfc3986.txt>)
    CFStringRef escaped =
    CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
                                            (CFStringRef)self,
                                            NULL,
                                            (CFStringRef)@"!*'();:@&=+$,/?%#[]",
                                            kCFStringEncodingUTF8);
    NSString *res = [NSString stringWithString:(__bridge NSString *)(escaped)];
    CFRelease(escaped);
    return res;
}

- (NSString*)_stringByUnescapingFromURLArgument;
{
    NSMutableString *resultString = [NSMutableString stringWithString:self];
    [resultString replaceOccurrencesOfString:@"+"
                                  withString:@" "
                                     options:NSLiteralSearch
                                       range:NSMakeRange(0, [resultString length])];
    return [resultString stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
}

- (NSString*)mul_md5Encode;
{
    return [[self mul_MD5Encode] lowercaseString];
}

- (NSString*)mul_MD5Encode;
{
	NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
	const char *cStr = [self cStringUsingEncoding:enc];
	unsigned char result[CC_MD5_DIGEST_LENGTH];
	CC_MD5( cStr, strlen(cStr), result );
	return [NSString stringWithFormat:
            @"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",
            result[0], result[1], result[2], result[3],
            result[4], result[5], result[6], result[7],
            result[8], result[9], result[10], result[11],
            result[12], result[13], result[14], result[15]
            ];
}

- (NSString*)toBase64String;
{
    NSData *data = [self dataUsingEncoding: NSUTF8StringEncoding];
    
    NSString *ret = [NSString base64StringFromData:data length:[data length]];
    
    return ret;
}

+ (NSString *)base64StringFromData: (NSData *)data length: (NSUInteger)length {
    static char base64EncodingTable[64] = {
        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
        'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
        'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
        'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
    };

    unsigned long ixtext, lentext;
    long ctremaining;
    unsigned char input[3], output[4];
    short i, charsonline = 0, ctcopy;
    const unsigned char *raw;
    NSMutableString *result;
    
    lentext = [data length];
    if (lentext < 1)
        return @"";
    result = [NSMutableString stringWithCapacity: lentext];
    raw = [data bytes];
    ixtext = 0;
    
    while (true) {
        ctremaining = lentext - ixtext;
        if (ctremaining <= 0)
            break;
        for (i = 0; i < 3; i++) {
            unsigned long ix = ixtext + i;
            if (ix < lentext)
                input[i] = raw[ix];
            else
                input[i] = 0;
        }
        output[0] = (input[0] & 0xFC) >> 2;
        output[1] = ((input[0] & 0x03) << 4) | ((input[1] & 0xF0) >> 4);
        output[2] = ((input[1] & 0x0F) << 2) | ((input[2] & 0xC0) >> 6);
        output[3] = input[2] & 0x3F;
        ctcopy = 4;
        switch (ctremaining) {
            case 1:
                ctcopy = 2;
                break;
            case 2:
                ctcopy = 3;
                break;
        }
        
        for (i = 0; i < ctcopy; i++)
            [result appendString: [NSString stringWithFormat: @"%c", base64EncodingTable[output[i]]]];
        
        for (i = ctcopy; i < 4; i++)
            [result appendString: @"="];
        
        ixtext += 3;
        charsonline += 4;
        
        if ((length > 0) && (charsonline >= length))
            charsonline = 0;
    }     
    return result;
}

@end
